This study presents a detailed numerical investigation into how blade twist angles affect the performance of a three-bladed C-rotor Savonius Vertical Axis Wind Turbine (VAWT). Utilizing Computational Fluid Dynamics (CFD) combined with the Finite Element Method (FEM), simulations were conducted across twist angles of 0°, 20°, 50°, and 70°, under wind speeds of 3 to 6 m/s. The results reveal that twisting the blades significantly enhances torque generation, rotor speed, and energy conversion efficiency. Notably, the 50° and 70° twisted configurations exhibited the highest performance, achieving power coefficients (C p ) of up to 3.94 and 3.87, respectively, along with torque values exceeding 21 Nm. In contrast, the non-twisted configuration displayed limited performance, with a maximum C p of only 0.195. Across all twist angles, the Tip Speed Ratio (TSR) remained relatively stable around 0.25, indicating consistent aerodynamic behavior. These findings highlight the effectiveness of geometric optimization in Savonius turbines, especially in low to moderate wind conditions, and underscore the potential of twisted rotor designs for improving small-scale wind energy systems.
Saepuddin et al. (2025) studied this question.